Lately, secondary batteries such as lithium-ion secondary batteries and nickel-hydrogen batteries, etc., have become increasingly important as, for example, power supplies loaded on electrically-driven vehicles, or as power sources loaded on PCs, mobile phones and other electric products, etc. In particular, lightweight lithium-ion secondary batteries with high energy densities are expected to be preferably used as high-power power supplies to be loaded on vehicles. Lithium-ion secondary battery, which is a typical example of such a non-electrolyte secondary battery, comprises electrodes (a positive electrode and a negative electrode) having electrode active material layers (a positive electrode active material layer and a negative electrode active material layer) primarily comprising electrode active materials (a positive electrode active material and a negative electrode active material) capable of reversibly storing and releasing a chemical species (lithium ions) serving as the charge carrier, and uses a non-aqueous electrolyte solution having a composition containing a support salt such as LiPF6 or the like in a non-aqueous solvent such as propylene carbonate, ethylene carbonate, etc. Patent Documents 1 to 4 can be cited as conventional art disclosing oil absorption numbers of positive electrode active materials or negative electrode active materials in such lithium-ion secondary batteries.